Patent GB-364846-A (GB)
Title: Improvements in or relating to automatic door opening apparatus
IPC: E05F15/14
Filed: 1931-01-10
Abstract: 364,846. Operating lift doors. WESTINGHOUSE ELECTRIC & MANUFACTURING CO., East Pittsburg, U.S.A.- (Assignees of Ellis, C. E.; Mahwah, New Jersey, and McCormick, H. V.; 573, La Fayette Boulevard, Long Beach, New York, both in U.S.A.) Jan. 10, 1931, No. 894. Convention date, Jan. 11, 1930. [Class 78 (iii).] In an automatic door-operating system for lifts, in which a separate motor is provided for the shaft door at each floor and for the cage door, all the motors are operated from a single control board, the circuit for the shaft door at any floor being selected by the slowing down of the cage on approach to that floor. At each floor an armature is provided, which closes contacts in the circuit for the motor at that floor when it is attracted by an inductor relay carried on the cage ; this relay is only energized when certain relays on the lift control board are de-energized on slowing down of the cage, so that the armatures at floors which the cage is passing are not operated. The circuit for the cage and shaft door motors is completed when further lift control relays are operated during levelling of the cage at the floor. The cage and shaft door motors are connected in parallel to operate together, and the resistance and inductance of the circuit are varied during operation of the doors to reduce the speed or vary the torque of the motors, under control of rotary switches operated by the cage door mechanism ; the motors are de-energized a short time after the doors reach their extreme positions, to ensure complete operation. The closing of the doors is initiated by a switch in the cage, or automatically on operating the lift control switch to start the cage. The Figure shows the door control apparatus in the position when the car is travelling at full speed ; the system is controlled by a master switch MS2, and the door operations are controlled by an opening switch ORS and a closing switch CRS, these switches being solenoid-operated under the control of relays DOR, DCR respectively. The apparatus in the cage includes a door motor M, and rotary switches RS1, RS2, RS3, driven by the cage door mechanism for control of the door circuits ; the inductor relay is shown at IR, and A is the armature at one of the floors, controlling the shaft door motor M2. R1 and R2 are relays which are normally energized from the lift control apparatus (not shown) when the cage is in motion, as shown ; Rl is connected so as to be de-energized when the cage slows down on approach to a floor, and R2 is deenergized as the cage is finally levelling at the floor. When relay R1 is de-energized, the inductor relay IR is energized across the power lines L1, L2, and the armature A at the floor at which the cage is to stop is attracted to close contacts in the armature and field circuits of the shaft door motor M2. When R2 is de-energized, as the cage finally reaches the floor, relay DOR is energized over rotary switch RSl, and this completes the circuit of switch ORS, which, therefore, operates. ORS closes a holding circuit for itself and DOR over its contacts b and contacts a of CRS, and closes a circuit for the motors M, M2 as follows : from L1, through contact e of MS2, field of M and contact a of MS2, and also through contact c of armature A and field of M2, to contacts e of ORS and thence through contact d of MS2, armature of M and contact b of MS2, and also through contact b of armature A and armature of M2, to contacts d of ORS and through resistance 46 to line L2. The armatures of the motors are thus connected in parallel in series with the fields in parallel, so that the 'two doors operate together. As the doors open, the switches RS1, RS2, RS3 are rotated anticlockwise. When the doors are about half open, RS3 completes a circuit containing a choking coil C3, contact c of MS2, resistances 53 and contacts c of ORS in parallel with the motor armatures; this checks the doors, and as their motion continues RS3 cuts out some of the resistance to increase the checking effect. When the doors are nearly open RS2 connects 45 in parallel with 46 to increase the torque of the motors to compensate for decreasing mechanical advantage, and finally RS1 opens the circuit of DOR. DOR is, however, maintained energized for a short time by choking coil C1, so that ORS keeps the motors energized for a while to ensure complete movement of the doors. The closing movement of the door is initiated by pressing a button MS3, or operating the lift control switch CS, to bridge the gap in the circuit of R2, which is, therefore, energized and closes the circuit of relay DCR to operate CRS. CRS completes the motor circuits in a similar way to the opening circuits but with the armatures reversed, and with the addition of a resistance 47 which is at first shunted by RS2 and then cut out to allow operation without acceleration. RS3 checks the doors as before, except that no torque-increasing resistance is used, and RS1 finally breaks the circuit of DCR and prepares that of DOR. The Specification also describes various mechanisms for operating the doors.